Quantitative local determination of these characteristics poses a major challenge in natural environments with a heterogeneous substrate. Geological knowledge on the natural genesis and resulting structure of the subsurface may provide useful information on the spatial variability of substrate characteristics. Here we describe a framework for using geological subsurface information for these assessments. Based on existing digital geological mapping products and knowledge of the geological development of the Rhine-Meuse delta. We then used these spatial divisions in an analysis of digital borehole data (>130.000 locations, UU-LLG dataset), to provide quantitative information on grain sizes of the very top of sand bodies and non-sand overburden thicknesses, split per subunit and summarized for sub regions (lower delta, central delta, upper delta, delta rim sectors). This framework enables us to demonstrate to what extent the median grain size of the top of sand deposits varies within the delta. The data is ...